The ancient remains of a teenage girl, researchers call her Naia, found deep in the water of a Yucatán Peninsula cave have established a definitive link between the earliest and modern Native Americans, according to a new study in Science.

So, yes, they really were here before you.

Ancient human remains in the Americas have been a puzzle for science because their skulls are narrower and have other measurably different features from those of modern Native Americans. Some researchers have hypothesized that these individuals came to the Americas from as far away as Australia, Southeast Asia or Europe.

Researchers analyzed the DNA from the tooth of the adolescent girl, who fell into sinkhole ,Hoyo Negro ("black hole") in Mexico’s Yucatán Peninsula more than 12,000 years ago. The remains were found surrounded by a variety of extinct animals more than 130 feet below sea level in the Sac Actun cave system in the Yucatán.

In three separate labs, the researchers independently examined the tooth’s mitochondrial DNA, which is maternally inherited (passed down from mother to child).

Each of the labs found that the ancient girl belonged to a genetic lineage shared only by Native Americans. This is the first time researchers have been able to match a skeleton with an early American (or Paleoamerican) skull and facial characteristics with DNA linked to the hunter-gatherers who moved onto the Bering Land Bridge from northeast Asia between 26,000 and 18,000 years ago, spreading southward into North America sometime after 17,000 years ago.

“The Hoyo Negro girl was related to living Native Americans and has ancestry from the same Beringian population,” says Deborah Bolnick, assistant professor of anthropology at The University of Texas at Austin. “This study therefore provides no support for the hypothesis that Paleoamericans migrated from Southeast Asia, Australia or Europe. Instead, it shows that Paleoamericans could have come from Beringia, like contemporary Native Americans, even though they exhibit some distinctive skull and facial features. The physical differences between Paleoamericans and Native Americans today are more likely due to changes that occurred in Beringia and the Americas over the last 9,000 years.”

The study was led by Mexico’s National Institute of Anthropology and History, and coordinated by James Chatters, owner of Applied Paleoscience, an archaeological and paleontological consulting firm in Bothell, Wash.